struct usbhsg_gpriv {
        struct usb_gadget        gadget;
        struct usbhs_mod         mod;
+       struct list_head         link;
 
        struct usbhsg_uep       *uep;
        int                      uep_size;
 #define usbhsg_status_clr(gp, b) (gp->status &= ~b)
 #define usbhsg_status_has(gp, b) (gp->status &   b)
 
+/* controller */
+LIST_HEAD(the_controller_link);
+
+#define usbhsg_for_each_controller(gpriv)\
+       list_for_each_entry(gpriv, &the_controller_link, link)
+#define usbhsg_controller_register(gpriv)\
+       list_add_tail(&(gpriv)->link, &the_controller_link)
+#define usbhsg_controller_unregister(gpriv)\
+       list_del_init(&(gpriv)->link)
+
 /*
  *             queue push/pop
  */
  *             linux usb function
  *
  */
-struct usbhsg_gpriv *the_controller;
 static int usbhsg_gadget_start(struct usb_gadget_driver *driver,
                            int (*bind)(struct usb_gadget *))
 {
-       struct usbhsg_gpriv *gpriv = the_controller;
+       struct usbhsg_gpriv *gpriv;
        struct usbhs_priv *priv;
        struct device *dev;
        int ret;
            !driver->setup      ||
            driver->speed != USB_SPEED_HIGH)
                return -EINVAL;
-       if (!gpriv)
-               return -ENODEV;
-       if (gpriv->driver)
-               return -EBUSY;
+
+       /*
+        * find unused controller
+        */
+       usbhsg_for_each_controller(gpriv) {
+               if (!gpriv->driver)
+                       goto find_unused_controller;
+       }
+       return -ENODEV;
+
+find_unused_controller:
 
        dev  = usbhsg_gpriv_to_dev(gpriv);
        priv = usbhsg_gpriv_to_priv(gpriv);
 
 static int usbhsg_gadget_stop(struct usb_gadget_driver *driver)
 {
-       struct usbhsg_gpriv *gpriv = the_controller;
+       struct usbhsg_gpriv *gpriv;
        struct usbhs_priv *priv;
-       struct device *dev = usbhsg_gpriv_to_dev(gpriv);
-
-       if (!gpriv)
-               return -ENODEV;
+       struct device *dev;
 
        if (!driver             ||
-           !driver->unbind     ||
-           driver != gpriv->driver)
+           !driver->unbind)
                return -EINVAL;
 
+       /*
+        * find controller
+        */
+       usbhsg_for_each_controller(gpriv) {
+               if (gpriv->driver == driver)
+                       goto find_matching_controller;
+       }
+       return -ENODEV;
+
+find_matching_controller:
+
        dev  = usbhsg_gpriv_to_dev(gpriv);
        priv = usbhsg_gpriv_to_priv(gpriv);
 
                }
        }
 
-       the_controller = gpriv;
+       usbhsg_controller_register(gpriv);
 
        ret = usb_add_gadget_udc(dev, &gpriv->gadget);
        if (ret)
        struct usbhsg_gpriv *gpriv = usbhsg_priv_to_gpriv(priv);
 
        usb_del_gadget_udc(&gpriv->gadget);
+
+       usbhsg_controller_unregister(gpriv);
+
        kfree(gpriv->uep);
        kfree(gpriv);
 }